Mitral annuloplasty, by implantation of a shaped annuloplasty ring, can be used to repair the mitral valve for treating functional mitral regurgitation. Annuloplasty prostheses, e.g., annuloplasty rings or annuloplasty bands, can be used as part of valvular reconstructive surgery to assist in the correction of heart valve defects such as stenosis and valvular insufficiency. The mitral valve includes a valve annulus and valve leaflets. Mitral regurgitation is the back flow of blood from the left ventricle to the left atrium through the mitral valve. Dilation of the mitral valve annulus can prevent competence of the valve but also results in distortion of the normal shape of the valve orifice.
In annuloplasty procedures the annulus can be remodeled using surgical techniques on the mitral valve and/or prosthetic treatments for the mitral valve. It has been show through clinical trials that the repair of the valve, when technically possible, produces better long-term results as compared to valve replacement. Even when other repairs to the mitral valve are made, most of the time annuloplasty is performed.
Annuloplasty can be performed by open surgical procedure, but less invasive and percutaneous approaches can also be used. One goal in annuloplasty is to make the mitral annulus smaller, particularly in the septal-lateral dimension. A number shapes of rings can be used, such as rounded D shape, and can include various small curves, out-of-plane saddle shapes, complete rings, and incomplete rings, among others, depending on patient requirements and physician preference. Also, a suture-based cinching procedure can be used to perform an annular reshaping similar to the prosthetic procedures.
Many percutaneous annuloplasty approaches place a rigid structure in the coronary sinus, which is near the mitral annulus. These procedures that place a rigid structure in the coronary sinus may not be effective or safe in all patients due to the anatomy of the coronary sinus, the mitral annulus, and the nearby circumflex coronary artery. In particular, coronary sinus devices may not be as effective as devices placed at the mitral annulus. Also, crossing of the coronary sinus over the circumflex artery can cause dangerous compression of the artery by a rigid annuloplasty device placed in the coronary sinus. The annuloplasty device must be quite stiff to be effective which presents difficulties in safely placing the device near the mitral annulus using a less invasive, percutaneous procedure.